Back in 2006, when I was Ohio EPA, I worked on Senate Bill 265 which was the first major overhaul in air pollution regulation in Ohio in over a decade. One component of S.B. 265 was to provide authority to Ohio EPA to regulate air toxics.

Prior to enactment of S.B. 265, Ohio EPA did utilize an "air toxics policy" that was used to evaluate whether an air pollution source should obtain a permit due to emission of certain air toxic compounds above certain thresholds. As a policy, the Ohio EPA did not have clear legal authority to enforce the requirement. After enactment of S.B. 265, the Ohio EPA was given that authority. The bill required the director to adopt a list within two years of passage of the bill of those air toxics that could trigger permitting.

There are literally thousands of compounds that could be considered toxic. Ohio EPA decided to rely upon toxicity information compiled by the American Conference of Governmental Industrial Hygienists ("ACGIH"") The toxicity value developed by ACGIH is referred to as a chemical's threshold limit value ("TLV"). The TLV represents the value to which a worker could be exposed without health effects.

However, TLVs are based upon worker exposure (8 hour and 5 day work week). Ohio EPA felt that the number could be too conservative for residential exposures (24 hours and 7 days a week). Therefore, Ohio EPA took the TLV for each compound and divided it by 10 as a "safety factor." The result is a standard Ohio EPA refers to as the Maximum Achievable Ground Level Concentration ("MAGLC"). This is the value which it believes a resident living near a facility would not experience health effects.

Ohio EPA Reduces the List of Toxics

With so many chemical compounds, Ohio EPA tried to concentrate on those they felt presented the greatest risk of health effects. Ohio EPA culled the list based on toxicity to 639 compounds. Then, utilizing various factors discussed below, Ohio EPA cut down the original list to 303 total compounds. See, OAC 3745-114-01.

The factors utilized to cut down the list to 303 compounds included:

If the compound was used in consumer products or regulated by other agencies (such as pesticides), then they were excluded;

If the only pathway for exposure was non-inhalation (i.e. dermal contact, ingestion);

If health effects are caused by exposure which is sudden and of short duration, such as those caused by emergency release events, including explosions or catastrophic malfunction (referred to as "acute exposure");

Compounds no longer used or produced in Ohio; and

Those compounds that only cause irritation, not serious health effects.

Legal Challenge

The Sierra Club filed a legal challenge to the final air toxic rule. The environmental group said the five factors used to cut the list from 639 to 303 compounds were unlawful.

The 10th Appellate Court upheld three out of the five factors. See, Sierra Club v. Koncelik The Court found that Ohio EPA should not have eliminated compounds simply because they currently aren't utilized in the State, because they may in the future. Also, the Court said that Ohio EPA should not have eliminated compounds that posed health effects only through non-inhalation routes of exposure (i.e. dermal contact or ingestion).

As a result of the Court ruling, Ohio EPA will be adding to the list of 303 compounds.